Question

Name the gas evolved is each of the following cases :
(i) Action of sulphuric acid on magnesium
(ii) Action of heat on lead oxide
(iii) Addition of concentrated hydrochloric acid on Pb₃O₄.
(iv) Addition of concentrated sulphuric acid to sodium chloride
(v) Zinc sulphide is treated with dilute hydrochloric acid.

Answer 1

Answer:

Hto gas

Oto gas

hto gas

hto gas

Answer 2

(i) H2 gas

(ii) O2 gas

(iii) H2O - water vapour

(iv) HCl gas

(v) H2S gas

Explanation:

(i) Magnesium reacts with dilute sulphuric acid to form magnesium sulphate and hydrogen gas is evolved.

(ii) Lead (IV) oxide is thermally unstable and it tends to decompose into lead(II) oxide and oxygen upon heating.  

(iii) Pb₃O₄ + 8HCl ⇒ 3PbCl₂ + 4H₂O + Cl₂ -- Steam

(iv) H2SO4(Aq)+NaCl(S)-> HCL(g)+Na2SO4(Aq)  -- Hydrogen chloride is produced as a gas.

(v) ZnS+2HCL→ZnCl2+H2S -- H2S gas will be evolved.